#include<stdio.h>
#include<stdlib.h>
struct TreeNode
{
    int data;
    struct TreeNode*left;
    struct TreeNode*right;
};
struct TreeNode*creatNode(int value)
{
    struct TreeNode*newNode=(struct TreeNode*)malloc(sizeof(struct TreeNode));
    newNode->data=value;
    newNode->left=newNode->right=Null;
    return newNode;
}
struct TreeNode*insert(struct TreeNode*root,int value)
{
    if(root==Null)
    return creatNode(value);
    if(value<root->data)
    root->left=insert(root->left,value);
    else if(value>root->data)
    root->right=insert(root->right,value);
    return root;
}
int search(struct TreeNode*root,int target)
{
    if(root==Null)
    return 0;
    if(root->data==target)
    return 1;
    else if(target<root->data)
    return search(root->data,target);
    else
    return search(root->right,target)
}
int main()
{
    int n;
    scanf("%d",&n);
    if(n<=0||n>10)
    {
        printf("Invalid input");
        return 0;
    }
    struct TreeNode*root=Null;
    int value;
    for(int i=0;i<n;i++)
    scanf("%d",&value);
    root=insert(root,value);
}
int target;
scanf("%d",&target);
if(search(root, target))
printf("found");
else
printf("not found");
return 0
}